V20 doesn't come with a dedicated.bat, so you will have to create one yourself.
1. First thing you do is go to your Desktop and right click.
2. Now, go to New ► Shortcut.
A window will pop up like this

3.
[Windows 7, Vista]In the box, type in EXACTLY (Or Copy & Paste)
"C:\Program Files (x86)\Blockland\BlocklandLauncher.exe" -dedicated -map bedroom
(You can change "bedroom" to any map you want.)
[Windows XP]In the box, type in EXACTLY (Or Copy & Paste)
"C:\Program Files\Blockland\BlocklandLauncher.exe" -dedicated -map bedroom
(You can change "bedroom" to any map you want.)
There you go! Just run the shortcut and you have a dedicated server!